1. Field of the Invention
The present invention relates to a track working machine for the controlled lowering of a track comprised of two rails fastened to ties supported on ballast. It comprises a machine frame, at least one undercarriage supporting the machine frame on the track for mobility in an operating direction, a track stabilization unit for compacting the ballast whereby the track is lowered, the track stabilization unit being vertically adjustably mounted on the machine frame and including rail-engaging roller tools subjected to substantially horizontal vibrations extending transversely to the machine frame and the track, and a broom vertically adjustably mounted on the machine frame, the broom being rotatable about an axis extending transversely to the machine frame and the track.
2. Description of the Prior Art
U.S. Pat. No. 4,953,467 discloses a track surfacing machine of this type. It comprises two track stabilization units mounted on the machine frame in succession in the operating direction centrally between front and rear undercarriages supporting the machine frame on the track. Respective vertically adjustable front and rear ballast plows are mounted on the machine frame between a respective undercarriage and the track stabilization units. Two brooms, which are rotatable about axes extending transversely to the machine frame and the track, precede the rear ballast plow and cooperate therewith to aid in the movement of the plowed ballast. Another broom rotatable about a transverse axis is mounted on the machine frame behind the rear undercarriage to sweep any ballast moved by the ballast plow onto the ties either into an adjacent crib or onto a transversely extending conveyor band which removes such ballast to the track shoulders. The sweeping action of the rear broom causes some ballast stones to be thrown into the area where the ferrous fastening elements fastening the rails to the ties are located. These ballast stones remain lying there and may interfere with subsequent track work.
U.S. Pat. No. 4,170,942 discloses a mobile track leveling, lining and ballast packing machine for the non-stop correction of a track, which has never been in commercial use. This machine comprises an arrangement for compacting ballast in a transverse direction from the ends of the ties towards the points of intersection with the rails and towards the cribs, which arrangement includes an elongated vibratory plate extending along the tie ends at each side of the track and arranged cooperatively to compact the ballast therebetween. A ballast plow precedes this ballast compacting arrangement for moving ballast transversely inwardly from the tie ends and a broom rotatable about a transverse axis is associated with this ballast plow. A track lifting and lining unit is arranged between the plow and the ballast compacting arrangement which is designed to be used instead of the conventional tie tampers. No track stabilization is provided in this machine.
Accepted German patent application No. 1,243,227, published Jun. 29, 1967, discloses a small machine for compacting ballast. It comprises a small machine frame on which a carrier for four vibratory surface compactors is vertically adjustably mounted for alignment with the points of intersection of each track rail with successive ties to compact the ballast around these points of intersection. Another light machine frame is linked to the front end of the small machine frame in the operating direction, and this light frame carries a ballast broom rotatable about a transverse axis for sweeping ballast off the surface of the ties. Neither controlled lowering of the track nor track stabilization can be effected by this surface compactor.